Polarization diversity antenna feed system



y 6 967 D D. D. HOWARD 3,320,553

POLARIZATION DIVERSITY ANTENNA FEED SYSTEM 3 Sheets-Sheet 1 Filed June 29. 1961 ORIGiNAL DEAN D. HOWAR D May 16, 1967 0. 0. HOWARD 3,320,553

POLARIZATION DIVERSITY ANTENNA FEED SYSTEM Filed June 29. 1961 3 Sheets-Sheet 2 RADAR SYSTEM INDICATOR INVENTOR DEAN D. HOWA R D BY MM 7 WTTORNEY May 16, 1967 o. 0. HOWARD POLARIZATION DIVERSITY ANTENNA FEED SYSTEM 3 Sheets-Sheet 3 Filed June 29, 1961 INVENTOR DEAN D. HOWA R D ATTORNEY United States Patent 3,320,553 POLARIZATION DIVERSITY ANTENNA FEED SYSTEM Dean D. Howard, 8914 Oak Lane, Oxon Hill, Md. 20022 Filed June 29, 1961, Ser. No. 123,077 6 Claims. (Cl. 33311) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes withoutthe payment of any royalties thereon or therefor.

This invention relates in general to antenna systems and in particular to antenna feed systems for radar apparatus wherein angle sensing is obtained with circularly polarized electromagnetic wave energy by a single horn radiator system.

This invention is an improvement over that described in the copending application Ser. No. 780,175, now Patent No. 3,274,604, filed Dec. 12, 1958 for Antenna Feed System, by Bernard L. Lewis. In this preceding application a novel single horn feed system is provided intended primarily for use with linearly polarized electromagnetic radiation.

Under certain conditions of operation, the use of linearly polarized electromagnetic wave energy is not altogether optimum, such being the case for example where some effect is encountered which causes a variation in the polarization of return energy relative to transmitted energy or where a polarization sensitive target is likely to be positioned at some indeterminate angle with respect to the plane of polarization of the energy emitted by the radar system. Such polarization characteristics are not by any means limited to radar systems per se because they are also to. be encountered in one form or another in other types of apparatus such as communication systems or the like or in fact in any system employing electromagnetic wave energy which is linearly polarized.

To avoid difficulties with linear polarization under situations such as those of the foregoing general types, it is frequently desirable to employ circular polarization of the electromagnetic wave energy involved. Such circular polarization may alleviate certain existing problems but it introduces new problems peculiar to that particular form of polarization. Systems designed for linear polarization operation do not ordinarily work to maximum efiiciency with circular polarization and in the case of a transmitter device, a transmitter designed initially to produce linear polarization may not even excite circular polarization electromagnetic wave energy in the transmission medium normally employed. In addition circular polarization operation of a radar system has certain advantages in avoiding undesirable effects of certain jamming devices.

To obtain such circular polarization in monopulse tracking radars with ordinary horn type feeds it is a common practice in the present state of the art to employ a plurality of horn devices say 5, with combination of energy being made in an appropriate manner to obtain the desirable polarization characteristics.

It will be recalled upon reference to the prior application above identified that one of the principal advantages thereof was that the simultaneous lobing information in two planes could be obtained with a single horn radiator rather than the plural horns then previously required even for that comparatively simple problem. By avoiding such previously necessary plurality of horns it was possible to obtain much improved operation without sacrificing system sensitivity and reliability. If one were now to employ horns such as those of the previous application for the production or utilization of circularly polarized energy much of the advantages of the prior application would be lost because in the present prior art method of doing such,

3,320,553 Patented May 16, 1967 the apparatus would of necessity return to a plural horn situation. Thus itis apparent that in order to preserve the single horn advantages which were provided by the apparatus of the above-identified application, some arrangement must be evolved whereby a single horn device could be employed to produce or utilize circularly polarized electromagnetic wave energy.

Accordingly, it is an object of the present invention to provide a single horn antenna system suitable for simultaneous lobing with circularly polarized electromagnetic energy.

Another object of the present invention is to provide a primary radio frequency radiator system of small size for circularly polarized electromagnetic wave energy.

Another object of the present invention is to provide a single horn primary radiator system for circularly polarized electromagnetic wave energgy which can be constructed with no dividing septums and which can be employed to derive lobing information.

Another object of the present invention is to provide a primary radiator for a simultaneous lobing locator system employing circularly polarized electromagnetic wave energy by means of which the overall antenna beamwidth and illumination of the secondary radiator can be readily adjusted.

Another object of the present invention is to provide a primary radiator for a simultaneous lobing locator system employing circularly polarized electromagnetic wave energy in which the radiator itself as well as the interconnections thereto have a broad frequency bandwith.

Another object of the present invention is to provide an antenna system for an object locator system employing circularly polarized electromagnetic wave energy which is also capable of independent simultaneous operation on horizontally and vertically polarized radiant energy.

Another object of the present invention is to provide a primary radiator system for a simultaneous lobing radar system employing circularly polarized electromagnetic wave energy in which signals of two dicerent frequencies may be radiated simultaneously without interaction therebetween.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIGS. 1, 2 and 3 show separate components of a first embodiment of the present invention which can be connected together as indicated provide a complete'apparatus.

FIGS. 4 shows a partially schematic representation of the combined apparatus of FIGS. 1, 2 and 3 while a second embodiment of the apparatus of the invention whose components are typified structurally in FIGS. 5, 6 and 9 are shown in part in FIGS. 7 and 8.

In accordance with the teachings of the present invention apparatus is provided for separately deriving azimuth and elevation error signals for horizontal and vertical polarization components of incident energy so that they may be analysed separately or combined or compared if desired.

With reference now to FIG. 1 of the drawings the apparatus shown therein is part of an exploded repre sentation of a complete embodiment of the invention, the subsequent FIGS. 2 and 3 comprising the balance of the overall apparatus typified being usable for transmission and reception of electromagnetic wave energy in a radar system. This apparatus of FIG. 1 contains a horn device 10 having a major axis of directivity 11 as indicated. For simplicity in explaining the invention the apparatus may be further described with particular reference to the receiving phase of operation it being understood that the apparatus can be employed in a radar system wherein both reception and transmission phases of operation are normally encountered in rapid alternation. Thus the horn will receive energy incident upon the open end thereof for the purposes of determining the direction of a distant object in relation to the axis of directivity 11. The horn 10 is tapered from a large mouth area to a smaller area in the region of a transverse plane identified by the reference character 12, the taper being for purposes of providing impedance matching where desired and also to provide desired directivity characteristics with regard to the angle of sensitivity of the apparatus.

To the small cross-sectional portion of the horn 10 in the region of the plane 12 is connected a section of square waveguide 13, this waveguide being proportioned of double the width for normal dominant mode propagation in such a manner as to be capable of propagating the 2,0 modes both for incident linearly polarized energy having its polarization in the horizontal plane which is typified by the double headed arrow 14 or in the vertical plane which is indicated by the double headed arrow 15. The significance and desirability of the 2,0 configuration propagation capability is that this and the 1,1 modes contain information relative to any discrepancy which exists in the direction of a target object or signal source relative to the horn major axis of directivity 11.

The apparatus of FIG. 1 contains in addition to those components previously described, four double dominant width ports identified in general by the reference characters 16, 17 and corresponding ports 18 and 19 located in the parallel sides of the rectangular Waveguide 13 opposite to the corresponding ports 16 and 17. Beyond the ports 16 to 19 the rectangular waveguide 13 is terminated by a plate 20 which together with the waveguides connected to the ports 16 to 19 provides an effective matched impedance closure or transition at the inner end of the waveguide 13.

With the waveguide 13 being of dimensions sufficient to support the 2,0 mode in orthogonally related planes and the ports 16 to 19 also being of double width, the ports are capable of transmitting output indicative of signals existant in the waveguide 13 in the TE TE and TM modes.

To derive the sum and difference signals corresponding to the horizontal polarization component the opposing ports 17 and 19 of FIG. 1 are connected to the apparatus of FIG. 2 which is basically a pair of U-shaped waveguide members with hybrid junctions disposed at their mid-points. A first U-shaped member contains the right angle member and a corresponding right angle member 26 not shown which couple respectively between the ports 17 and 19 of FIG. 1 and a pair of parallel-disposed 2,0 with rectangular waveguides 27 and 28. The rectangular waveguides 27 and 28 taper by means of transition sections 29 and 30 to parallel 1,0 width rectangular waveguides 31 and 32 which in turn are connected via right angle transition devices 33 and 34 to the magic-T indicated in general by reference character 35.

The second U-shaped member of the apparatus of FIG. 2 connects to the 2,0 waveguides 27 and 28, the connections being made via ports 36 and 37 dis-posed in the broad walls of the waveguides 27 and 28 with the transverse (width) dimension of the second U-shaped member being parallel to the longitudinal axes of the waveguides 27 and 28.

This second. U-shaped member is basically a hybrid junction plus two 1,0 width rectangular waveguides 38 and 39 coupled to the waveguides 27 and 28 by port 36 and a corresponding port 37 in Waveguide 28 indicated in a dotted presentation. These ports 36 and 37 thus connect through the waveguides 38 and 39 by suitable right angle devices to a hybrid junction 40.

In operation of the apparatus of FIG. 2 in combination with that of FIG. 1 the energy of all modes involved in input signals having horizontal polarization are extracted together through the two double width guides connected to ports 17 and 19. The TE and TE modes couple to the ports 17 and 19 and waveguides 27 and 28 out of phase while the TE and TM modes couple to the two ports in the form of TE modes which are in phase. The original TE and the TE and TM as converted to TE propagate through the waveguides 27 and 28, and waveguides 31 and 32, however, the TE mode requiring a larger width dimension waveguide than that of the waveguides 31 and 32 will not propagate through the waveguides 31 and 32 but rather will be reflected by the transitions 29 and 30 to couple out of the side waveguides 38 and 39 in the TE mode. This coupling is out of phase to the two waveguides 38 and 39 and when this TE energy representative of the energy in the original TE mode in waveguide 13 is combined in the difference arm of the magic-T 40, the difference between the original TE mode signal from ports 17 and 19 appears in the output 41.

As to the original TE energy and the TE and TM modes as converted into TE propagated through the waveguides 31 and 32, the original TE mode couples to the waveguides 27 and 28 out of phase and when combined in the difference port of the magic-T appears at the output 42. On the other hand the TE energy of the original TE and TM modes couples to the waveguides 27 and 28 in phase to appear at the sum port 43 of the magic-T 35.

The character of the signals derived from the ports 41, 42 and 43 and their relations to the sum and the azimuth and elevation error signals are in general as follows: The output port 42 with its TE mode energy is the sum port providing the basic information that a signal source with a horizontal polarization component exists which is producing energy incident upon the horn 10. The output at 41 is the elevation error signal for the horizontal polarization component whereas the output signal obtained from port 43 is the azimuth error signal for the horizontal polarization component.

With reference now to FIG. 3 of the drawing, the apparatus shown therein is the third portion of a basic embodiment typifying the invention, this apparatus including the components of the overall device connected to the ports 16 and 18 of the previously described FIG. 1, which is indicated by dotted lines in FIG. 3.

The ports 16 and 18 of the apparatus of FIG. 1 are .connected to the portion shown in FIG. 3, in particular to the waveguides 50 and 51 which respectively are connected to the ports 16 and 18 through suitable right angle transition devices 52 and 53. As with the waveguides 27 and 28, the waveguides 50 and 51 are of sufficient width to support the TE mode which propagates therethrough from the ports 16 and 18 in response to energy incident upon the open mouth of horn 10 of FIG. 1 from certain directions other than the axis 11. The waveguides 50 and 51 are connected to two hybrid junctions indicated in general by the reference characters 54 and 55 which in general correspond to the hybrid junctions 35 and of FIG. 2.

Between the waveguides 5t and 51 and the hybrid junction 54 are disposed two transition sections identified by the reference characters 56 and 57 which provide a transition between the larger waveguides and 51 and the smaller TE waveguide portions connecting to the hybrid junction 54 which need support only the basic TE mode. In addition the transition sections may be described as containing right angle transition portions. In the hybrid junction 54 which is typically of the magic-T type, connections to two output ports 58 and 59 are shown.

In addition to the magic-T 54, the magic-T is connected to the waveguides 5t) and 51 as above noted be ing disposed with the broad walls of the basic TE mode dimensioned waveguide structure thereof parallel to the longitudinal axes of the waveguides 50 and 51 and connected in the broad walls of the waveguides 50 and 51. In this instance only one output port is required for the hybrid junction 55 and that one is connected to the output port 60 through an offset structure to avoid Waveguide 31. Should it be desired to use a magic-T for this hybrid 55 the unused narrow wall port could be terminated in a matched impedance if desired to provide absorption of various signals which could exist therein due to impedance mismatches and other reasons.

The coupling provided by the waveguides and hybrid junctions of the apparatus of FIG. 3 is somewhat similar to that of the apparatus previously described in FIG. 2, however, the signals derived at the various output ports 58, 59 and 60 differ significantly from those of FIG. 2. In general the basic coupling to the double dominant width waveguides 50 and 51 is out-of-p-hase for the two guides or ports 16 and 18 for the original TE and TE modes in the square guide 13 while the TE and TM modes of the square guide 13 couple to the ports 16 and 18 in-phase in the form of TE modes. The original TE mode energy thus fed to waveguides 50 and 51 out of phase is reflected by the reducing transitions 56 and 57 to the junction 55 from whence it is withdrawn through the difference output to appear at port 60 as the azimuth error signal for incident vertically polarized energy or for the vertical component of circularly polarized energy. The TE mode is not reflected by the reducing portions of transitions 56 and 57 but continues through to the hybrid junction 54 where it couples out through the difference port of the hybrid 54 to appear at output port 58 as the sum signal for incident vertically polarized energy or for the vertical component of circularly polarized energy.

Because of the in-phase coupling of the TE and TM modes existing in the waveguide 13 to the waveguides 50 and 51 these signals are excited as basic TE mode energy which is capable of proceeding to the hybrid junction 54 from whence it is withdrawn through the sum" port of the hybrid junction 54 to appear at output port 59 as the elevation error signal for the vertical polarization component or for the vertical component of circularly polarized energy.

With reference now to FIG. 4 of the drawings, the apparatus shown therein indicates how the various sum and' error signals produced by the previously described portions of apparatus shown in FIGS. 2 and 3 are combined for utilization. Although it is readily apparent to one skilled in the monopulse radar art that the pairs of Elevation Error, Azimuth Error and Sum signals could be combined and fed directly to a monopulse radar, such is not the only utility since many different indications could be advantageous such as displaying the pairs in orthogood deflection axes on Oscilloscopes and the like. The auxiliary circuitry is thus capable of assuming many and diverse forms with various combinations of the six signals available. FIG. 4 indicates a simplified arrangement with mixers 70, 71, and 72 for the pairs and a single indicator 73 including possibly cathode ray tubes for signal analysis.

With reference now to FIG. 5 of the drawings, the apparatus shown therein is a representation of a portion of apparatus constituting a second embodiment of the principles of the present invention, this portion together with the subsequently described FIGS. 6 and 7 representing a complete second embodiment. The apparatus of FIG. 5 contains a horn portion 100 shown partly cut-away which provides for impedance matching and di rectivity characteristics in coupling to space or illuminating a lens or reflector. This horn 100 is connected to a first square waveguide portion 101 which in turn is connected via a transition section 102 to a second square waveguide 103 of cross sectional dimensions somewhat smaller than those of the waveguide 101. In turn the waveguide 103 is connected via a further transition sec- 6 tion 104 to a section of preferably circular waveguide 105.

The dimensions of the square waveguides and the circular waveguide are such that the waveguide 101 is of double the dominant mode width and height and therefore capable of transmitting the TE mode in both the vertical and horizontal planes or dimensions thereof upon appropriate excitation at the horn 100. The square waveguide section 103 is of an intermediate dimension between the double! width mode and the single width mode dimensions being equal approximately to /2 times the normal dominant mode width permitting this sec tion to propagate energy in the TE and TM modes. The circular waveguide 105 is of a diameter that will propagate the dominant circular mode at the frequency involved but which will not propagate higher order modes. If of circular configuration it is capable of transmitting energy without rejection as to plane of incident energy or sense of polarization thereof. Energy incident upon the horn is capable of progressing through the waveguides 101 and into waveguide still maintaining its original plane or sense of polarization. In a manner of speaking then, the transition sections and reduced dimension waveguides that follow constitute filters which reject the higher order modes so that only the basic mode is propagated in the waveguide 105.

Coupling to the various modes existent in the waveguides of the apparatus of FIG. 5 is provided by arrangements similar to those of the previously described FIGS. 1, 2 and 3. In general it is stated that the square waveguide 101 has four ports identified by the reference characters 116, 117, 118 and 119 and which in general are numbered so as to indicate correspondence to ports of FIG. 1 however, in this instance there is no true identity between the signals of these ports and those of FIG. 1. Basically original TE mode energy couples out of the large square cross-section guide 101 as TE signals via the ports 116, 117, 118 and 119. The ports 116 through 119 are of rectangular configuration having a major crosssectional dimension corresponding to that normally employed for propagation of the TE mode in a waveguide at the frequencies involved. This major dimension of the ports is disposed parallel to the longitudinal axis of the waveguides 101, 103 and 105 and each port is disposed substantially centrally in the corresponding face of the square waveguide. In the basic FIG. 5 the ports 116 through 119 are all located in substantially the same plane along the longitudinal axis of the guide however, it will be subsequently explained that in some instances it may be desired to lengthen the waveguide 101 and stagger the ports 117 and 119 relative to the ports 116 and 118 along the longitudinal axis to provide certain conveniences in the configuration of the waveguides leading from the paired ports to the hybrid junctions which provide appropriate combinations of the signals taken from the paired ports.

The TE mode energy coupling as out of phase TE energy at the ports 117 and 119 corresponds to a horizontal polarization component of the incident signal. The signals from the two ports 117 and 119 are delievered by suitable waveguides to a magic-T hybrid junction for ex- .ample as indicated in general by the junction 120 in FIG.

6. When this signal obtained out of phase at the ports 117 and 119 is combined in the hybrid junction 120 it will couple out of the difference port 121 of FIG. 5 as the elevation difference signal for the horizontal component of polarization. The sum port 122 is not required in this instance and may be omitted.

The top and bottom ports 116 and 118 of the square waveguide 101 couple to TE mode energy excited in the waveguide by the vertical polarization component of the incident energy providing an azimuth difference signal. This azimuth difference signal can be coupled from the ports 116 and 118 in the TE mode and combined in a magic-T device such as that shown in FIG. 6. With the ports 116 through 119 located in substantially the same longitudinal plane it is impractical to employ two devices of the exact configuration of the U-shaped member of FIG. 6 coupling to the ports 117 and 119 because of mutual physical interference. Thus it would be desirable to stagger the ports for the horizontal and vertical polarization components along the longitudinal axis of the waveguide 101 or possibly employ offsetting waveguide structures such as those shown in FIG. 6 for ports 116 and 118. Such can be assembled from components now well known in the art and available commercially. In any event the net effect is to obtain appropriate combination of the signals from the ports 116 and 118 in a suitable coupling device such as a magic-T by means of which the azimuth error signal for the vertical polarization component can be extracted in one port comparable to that of port 121 of the basic U-shaped structure of FIG. 6. This is indicated schematically by the lines connected to the magic- T 123 in FIG. 6.

As before, the sum port of the magic-T 123 is not required and can be blocked or omitted.

FIG. 7 indicates in schematic form the signal paths which are employed for the utilization of the error signals carried by the original TE mode signals. In correspondence with FIGS. and 6, ports 116, 117, 118 and 119 are indicated as are the magic-T devices 120 and 123, it being understood that there is no difficulty or requirement as to specific physical placement of the magic-T 120 above or below the square waveguide 101, the location being selected for convenience for the particular configuration employed. The TE mode signal in the difference output port 121 of magic-T 120 is the elevation error signal derived from the horizontal polarization component of the energy incident upon the horn 100 and excited in the square waveguide 101 as a TE signal.

The magic-T 123 as shown is connected to the ports 116 and 118 and the schematically indicated difference port 124 thereof derives an output in dependency on the TE mode component excited in the square waveguide 101 by the vertical polarization component of the energy incident upon horn 100 and is the azimuth error signal. The fourth port 125 of the magic-T 123 is unnecessary and can be omitted.

As shown in FIG. 5 the square waveguide 103 contains the ports 126, 127, 128 and 129 with ports 127 and 128 being disposed in faces of the square waveguide which are not visible due to the orientation of the apparatus. These are indicated together with the visible ports in the corresponding schematic presentation of FIG. 8 which can be compared to a representation of the overall apparatus in the region of square waveguide 103 containing the ports and to which attention is now directed.

The square waveguide 103 is of such proportions as to prevent the propagation therein of the TE mode energy, however, side ports 127 and 129 will couple in phase to the 1,1 modes existing in the square waveguide 103 resultant to the horizontal polarization component of incident energy. The energy coupling in phase from the ports 127 and 129 is applied to a magic-T 130 from whence it couples out through the sum port 131 to provide the azimuth error signal as derived from the horizontal component of incident electromagnetic wave energy. The magic-T 130 also contains a fourth port identified by the reference character 132 from which is coupled some energy resultant to TE mode energy incident on the horn 100 resultant to the horizontal component of incident polarized energy. This TE mode energy can be refiected in an appropriate manner to obtain beam shaping to minimize ellipticity of the beam or to render the port 132 effectively non-absorptive of incident energy.

The ports 126 and 128 of the square waveguide 103 are connected to a magic-T 133. The TE and TM mode energy excited in the waveguide structure as a result of the vertical polarization component of incident electromagnetic wave energy couples in phase from ports 126 and 128 and upon application to the magic-T 133 is withdrawn at the sum port 134, the difference port 135 providing a signal in dependency upon the incident excitation in the TE mode resultant to the horizontal polarization component of incident electromagnetic wave energy. As previously noted this energy can be used for beam shaping or other purposes. The energy obtained at port 134 is the elevation error signal corresponding to the vertical polarization component of incident electromagnetic wave energy upon the horn of FIG. 5.

It is interesting to observe that the ports placed in the square waveguide 103 are disposed with their width dimensions at right angular relationship to those of the ports in the square waveguide 101. This is characteristic of the couplings required for the various modes involved and need not be elaborated on further at this point. As with the previously discussed waveguide 101 it is appropriate to observe that the top and bottom ports 126 and 128 may be staggered along the length of the square waveguide 103 relative to the ports 127 and 129 for convenience in construction of the necessary waveguide structures required for utilizing properly the signals existent at the ports 126 through 129. Alternately other forms of extraction devices rather than the staggered ports could be employed such being similar for example to the arrangements of FIG. 6, the exact configuration being normally a matter of design and convenience for the particular structure involved.

FIG. 9 shows a representation of the waveguide portion of the apparatus of FIG. 5 through which energy is propagated in a plane characteristic of the plane of polarization of electromagnetic wave energy incident upon horn 100. Although this waveguide 105 has been shown as being circular, configurations such as square could be employed. This signal propagates through the waveguide 105 for delivery as the monopulse sum signal for a typical monopulse radar system. It is important to note that this signal retains polarization information possessed by the incident energy so that upon appropriate analysis in apparatus such as an instantaneous polarimeter it is possible to determine the polarization nature of the sum component of the incident signal or to utilize it directly without requiring such analysis as the basic sum signal for the monopulse radar system, it being understood that such monopulse radar systems are also well known in the art.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. In combination, a first waveguide capable of propagating energy in the TE TE and combined TE and TM modes in orthogonal planes, secondary waveguide means for coupling to the TE and combined TE and TM modes in the first waveguide, tertiary waveguide means for separately extracting TE mode energy of the first waveguide of the separate orthogonal planes, and means for coupling said tertiary waveguide means to the first waveguide.

2. In combination, a first waveguide capable of propagating energy in the TE TE and combined TE and TM modes in orthogonal planes, first and second pairs of secondary waveguides coupling to said first waveguide in separate orthogonal planes one pair for one plane the other pair for the other plane for extracting the TE energy of said first waveguide out-of-phase as to the members of a pair, for extracting the TE energy of said first waveguide out-of-phase as to members of a pair and for extracting the TE and TM energy of said first waveguide as TE energy in-phase as to members of a pair; and combining means connected to said secondary waveguides for providing sum combination of the T13 and TM energy from the first waveguide as extracted by the secondary waveguides and difference combination of the energy in separate lines of the TE and TE energy as extracted from the first Waveguide by the secondary waveguides.

3. In combination, a first waveguide capable of propagating energy in the TE TE and combined TE and TM modes in orthogonal planes, a second waveguide capable of propagating energy in the TE and combined TE and TM modes in orthogonal planes and incapable of propagating energy in the TE mode, means for coupling said second waveguide to said first waveguide, tertiary waveguide means for separately extracting TE mode energy of the first waveguide of the separate orthogonal planes, and means for extracting TE and TM mode energy of the first and second waveguides from the second Waveguide separately for the orthogonal planes of the first waveguide.

4. In combination, a waveguide capable of propagating energy in the TB TE and combined TE and TM modes in orthogonal planes, first and second ports for coupling to said modes in said waveguide in the first orthogonal plane, third and fourth ports for coupling to said modes in said waveguide in the second orthogonal plane, first secondary waveguide means connected to said first and second ports for transmission of TE and combined TE and TM energy of said waveguide in the first orthogonal plane, first tertiary waveguide means connected to said first secondary waveguide means for transmission of TE energy of said waveguide in the first orthogonal plane, second secondary waveguide means connected to said third and fourth ports for transmission of TE and combined TE and TM energy of said waveguide in the second orthogonal plane, and second tertiary waveguide means connected to said second secondary waveguide means for transmission of TE energy of said Waveguide in the second orthogonal plane.

5. In combination, a first waveguide capable of propagating energy in the TB TE and combined TE and TM modes in orthogonal planes, a second waveguide capable of propagating energy in the TE and combined TE and TM modes in orthogonal planes and incapable of propagating energy in the TE mode, means for coupling said second waveguide to said first Waveguide, tertiary waveguide means for separately extracting TE mode energy of the first waveguide in the separate orthogonal planes, means for extracting TE and TM mode energy of the first and second waveguides from the second waveguide separately for the orthogonal planes of the first waveguide, a third waveguide capable of propagating the TE mode in orthogonal planes and rejecting higher order modes, and means for coupling said third waveguide to said second waveguide.

6. In combination, a first waveguide capable of propagating energy in the TB TE and combined TE and TM modes in orthogonal planes, secondary waveguide means for coupling to the TE and combined TE and TM modes in the first waveguide, tertiary waveguide means for separately extracting TE mode energy of the first Waveguide of the separate orthogonal planes, means for coupling said tertiary waveguide means to the first waveguide, and means for providing paired coordination of the extracted energy whereby the TE mode energy for the two orthogonal planes is coordinated and the TE mode energy of each orthogonal plane is coordinated with the combined TE and TM mode energy of the other orthogonal plane.

References Cited by the Examiner UNITED STATES PATENTS 3/1960 Miller 34316.1 

1. IN COMBINATION, A FIRST WAVEGUIDE CAPABLE OF PROPAGATING ENERGY IN THE TE10, TE20 AND COMBINED TE11 AND TM11 MODES IN ORTHOGONAL PLANES, SECONDARY WAVEGUIDE MEANS FOR COUPLING TO THE TE10 AND COMBINED TE11 AND TM11 MODES IN THE FIRST WAVEGUIDE, TERTIARY WAVEGUIDE MEANS FOR SEPARATELY EXTRACTING TE20 MODE ENERGY OF THE FIRST WAVEGUIDE OF THE SEPARATE ORTHOGONAL PLANES, AND MEANS FOR COUPLING SAID TERTIARY WAVEGUIDE MEANS TO THE FIRST WAVEGUIDE. 